From e489babf9bdac926a27a4895bcc1f557e4598e13 Mon Sep 17 00:00:00 2001 From: Jim Grosbach Date: Mon, 5 Dec 2011 22:16:39 +0000 Subject: [PATCH] Thumb2 prefer ADD register encoding T2 to T3 when possible. rdar://10529664 llvm-svn: 145860 --- .../lib/Target/ARM/AsmParser/ARMAsmParser.cpp | 20 +++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp index cd6752a241c1..c1a745216e83 100644 --- a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp +++ b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp @@ -5238,6 +5238,26 @@ processInstruction(MCInst &Inst, return true; } break; + case ARM::t2ADDrr: { + // If the destination and first source operand are the same, and + // there's no setting of the flags, use encoding T2 instead of T3. + // Note that this is only for ADD, not SUB. This mirrors the system + // 'as' behaviour. Make sure the wide encoding wasn't explicit. + if (Inst.getOperand(0).getReg() != Inst.getOperand(1).getReg() || + Inst.getOperand(5).getReg() != 0 || + (static_cast(Operands[2])->isToken() && + static_cast(Operands[2])->getToken() == ".w")) + break; + MCInst TmpInst; + TmpInst.setOpcode(ARM::tADDhirr); + TmpInst.addOperand(Inst.getOperand(0)); + TmpInst.addOperand(Inst.getOperand(0)); + TmpInst.addOperand(Inst.getOperand(2)); + TmpInst.addOperand(Inst.getOperand(3)); + TmpInst.addOperand(Inst.getOperand(4)); + Inst = TmpInst; + return true; + } case ARM::tB: // A Thumb conditional branch outside of an IT block is a tBcc. if (Inst.getOperand(1).getImm() != ARMCC::AL && !inITBlock()) {